If the patient wears contact lenses and has glasses also, he or she is instructed not to wear the contact lenses on the day of the assessment. Patients unwilling to discontinue contact lens use after surgery will be excluded from the study. In the event that the patient either has no glasses or has forgotten the instructions and reported for the assessment wearing contact lenses, the contact lenses are removed and at least thirty minutes allowed to elapse before subjective refraction and visual acuity testing is performed.